U.S. Department of Energy - Energy Efficiency and Renewable Energy

Geothermal Technologies Office

Tapping the Earth's geothermal energy

July 29, 2008

LAKE COUNTY, CA (KGO) -- During this oil crisis, we've been searching for alternatives like wind, solar and even tidal power. But on Tuesday, officials from the federal government were in Lake County checking out a natural wonder -- an underground source of energy.

In the rugged woodlands of Lake County, hot springs bubbling from the ground are common, like a miniature Yellowstone. "There is an almost inexhaustible supply of heat beneath the surface," says geologist Joe Beal of Calpine. Calpine takes that steam and makes electricity at the world's largest geothermal power complex. Eighty miles of steam lines feed 19 separate power plants and generate more than two percent of California's electricity.

The beauty of geothermal energy in a place like this is that it is so easy to get to. Water and heat is right below the surface. But, could we tap more difficult sources? "M.I.T. did a study showing that 20 percent of electricity that is needed in the country can be generated from geothermal," says Ed Wall from the U.S. Department of Energy. Ed Wall came here to the Bay Area with $90 million of research money available over a four-year period.

Both the government and Calpine are interested in a section of land here, that while hotter and deeper, has no steam, but plenty of potential. "What we're trying to do is engineer reservoirs," says Wall. It's just a matter of pumping the water in and breaking up the solid rock below and creating steam. It's a massive undertaking. "We're talking about fracturing the order of cubic miles," says Beal. However, it offers a huge payoff.

If engineers perfect the process here, they could apply it almost anywhere on the continent. Instead of burning gas of coal to turn turbines, we could mine the planet's heat, creating emission-free electricity. "Sometimes nature helps you along, and sometimes you help nature along," says Beal. It's one possible answer to our present day energy woes from a million-year-old, natural miracle.

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